When it is empty we top it up again at the specific date exchange rate and so on.

We have configured a journal (EUR) and an account (EUR) for this e-wallet.

For expenses out of this account, we add manual journal entries by (we are referencing the names of fields under "journal entry" form) adding the EUR amount of the expense under "Amount Currency" and defining the "Currency" as EUR.

We notice that there is no auto conversion from EUR to company currency. We define with - (minus) or no sign the credit entry and the debit lines, but in those lines the actual debit and credit amounts are not filled in (they remain zero in all lines)